you have energy input. this task - the head can rotate and slide away. >> three, two, one, go. >> remember this 100 g hit? professor dumis has a 5-star helmet reducing it bias much as 50%, that's because the shell riskful. >> there are helmets that reduce your risk. like 5-star cars reduce your risk of dying in a car crash. >> as for blake lawrence, the risks of the game that he had, decision. >> our head coach said, "your concussions are happening too easily. that summer, before my junior ner at nebraska, i told myself and my family and the coaches and doctors if i had one more concussion, no matter the circumstances, i'd step away from the sport of football. it was easy to say, not do. >> looking at that peerks watching it, i -- piece, just watching it, i feel that gave me a head ache. >> rachelle, you have a background in neuroscience, what damage are we looking at with a big collision? >> that's interesting. there are thousands of researchers across the country trying to figure it out. some believe ther